Field of the Invention
The present invention relates to a nickel-base superalloy with little or no rhenium content.
Prior Art
Hard use conditions prevail in gas turbines such as stationary gas turbines for power generation or aircraft engines for the material used because these materials are exposed to high mechanical loads and high temperatures at the same time, in particular for the rotor blades, so that in addition to a high strength, a sufficiently high phase stability as well as creep resistance and oxidation resistance of the material are required.
To do justice to these requirements, nickel-base superalloys, for example, are used, optionally as single-crystal alloys or as directionally solidified alloys. These alloys have a high strength due to their alloy constituents because of the mixed crystal hardening and/or precipitation hardening or particle hardening. In addition, such nickel-base superalloys are optimized, so that the particle hardening is preserved due to the mixed crystal hardening and/or precipitation hardening or particle hardening due to their alloy constituents. In addition, such nickel-base superalloys have been optimized to the extent that the particle hardening is preserved due to the precipitation of so-called y′ phases, even at high temperatures and with long use times.
Examples of such alloys include nickel-base superalloys such as CMSX-4, PWA-1484 or Rene N5. All of these alloys have a rhenium content of more than 3% by weight.
However, the cost of materials is very high due to the high rhenium content, so there have already been proposals for developing nickel-base superalloys having little or no rhenium content. Examples of this are described in EP 2 305 848 A1, EP 2 218 798 A2, WO 2009/032578 and WO 2009/032579.